1. Field of the Invention
This invention relates to a mutant Escherichia coli SS373 and the production of succinic acid by using the above strain. In detail, a novel E. coli SS373 (W3110 pta::Tn10 ldhA::Km) with the deficiency in the acetate and lactate forming pathways was constructed by genetic engineering technique. An aerobically grown SS373 was then cultured by means of the anaerobic condition shift during the succinate producing stage, which resulted in the efficient production of succinic acid with a higher yield.
2. Description of the Prior Art
Succinate is one of the basic metabolites and an intermediate in the TCA cycle of the biological system. In the petrochemical industry, succinate serves a precursor of 1,4-butandiol. tetrahydrofuran, xcex3-butyrolactone. It is also useful as an ingredient in the food and cosmetic industry. Succinic acid is commercially produced by a chemical process. Recently the biological process has been of interest for an environmentally clean process. In addition. the biological process could produce succinate from low-cost renewable resources. For the reasons of as above, the biological succinate production has been intensely studied in the recent years. Among these studies, strict anaerobic Anaerobiospirillum succiniciproducens has been particularly well examined (U.S. Pat. Nos. 5,573,931, 5,521,075, 5,504,004). A. succiniciproducens, however, has a complex nutrient requirement and slows growth rate as well as difficulty in the production process associated with the strict anaerobe.
To solve the problems of a strict anaerobe in the succinate production, a facultative anaerobic E. coli was genetically engineered. By using the mutated E. coli, the succinate production with higher yield was achieved. Therefore, the objective of the invention herein is the construction of a mutant E. coli and enhanced production of succinate by using the mutant E. coli.